According to the British Compressed Air Society, approximately 70% of all companies use compressed air for some aspect of their operations, recognising that it is a safe and reliable source of power.
Compressor performance, therefore, has a key role to play in the overall cost efficiency and productivity of a process or plant. Industry figures estimate that many compressed air systems can waste up to 30% of the compressed air through leaks, poor control, poor maintenance or simply having the wrong compressor for the task.
As energy can represent over 70% of a compressor’s lifecycle costs, optimising electricity consumption is essential.
Just Trays
In a recent case study, Just Trays, the UK’s leading manufacturer of shower trays was on target to achieve annual energy savings in the region of £23,000 after installing a new L75RS regulated speed compressor with heat recovery from CompAir, with a fast payback on return on investment.
Compressed air is used throughout Just Trays’ manufacturing process to help produce over 800 models of shower tray in six ranges, from engineered installation solutions through to hand-made contemporary designs.
The plant’s existing unit, which was around 20 years old, was no longer providing an efficient source of air, so Just Trays opted to review its compressor system.
Following a week long audit, CompAir identified that, by installing a new, lubricated screw L75RS regulated speed compressor, as well as a heat recovery system, Just Trays could benefit from considerable energy savings.
Working 10 hours per day, 4 days per week, the regulated speed technology in the L75RS produces the correct amount of air to match our fluctuating requirements and peak demand of approximately 12.5 m3/min, meaning the compressor is always running at optimum efficiency. This is set to provide cost savings in the region of £15,000 per annum.
In addition, using heat exchangers, CompAir was able to develop a system to recover the heat produced during the compression process.
This heat is transferred to Just Trays’ vacuum forming process, whereby a sheet of plastic is heated to a forming temperature, stretched onto a single-surface mould and held against the mould by applying vacuum between the mould surface and the sheet.
Prior to the CompAir installation, Just Trays’ vacuum forming process required the use of four 9kw heat exchangers to achieve the required water temperature of up to 90°C.
The heat recovery system installed by CompAir enables the water feed to be preheated, meaning only one heat exchanger is required, providing additional savings of over £7,000 per annum.
RF2M Technologies
In another example of energy savings achieved through the installation of efficient compressor technology, RF2M Technologies, a manufacturer of electronic components for the defence-aerospace sector, reduced costs by £30,000 per year after switching to a CompAir L75RS regulated speed compressor with heat-recovery system.
The system has been so successful that the customer has recently invested in a second L75RS compressor to achieve even greater energy savings.
Part of the global API Technologies group, the site at Great Yarmouth has been manufacturing sensitive, high-tech electronics since the early 1980s. Operating 24 hours a day, seven days a week, RF2M has high-demand for a reliable source of instrument air which must also be highly efficient to ensure energy consumption remains as low as possible.
In 2007, the customer invested in its first CompAir L75RS regulated speed compressor, which was one of the first in the industry to have a heat recovery system fitted.
In the first year alone, the customer saved over 370,000 KWh of electricity on an average 35% compressor consumption rate, with a high percentage of this saving attributed to the efficient, regulated speed technology.
Using heat exchangers, CompAir distributor, Rodwell Bayne, was able to
develop a system to recover energy that would usually be wasted in the compression process and reuse it as a source of factory heating, reducing the requirement on the site’s gas boiler.
RF2M’s site manager, David Yates said, “Despite average colder winter temperatures over the past few years, the heat recovery system is still saving up to £3,000 per annum in gas consumption. Additional savings are also expected in 2013 as we now supply our nitrogen generation plant directly from the factory-air supply, rather than using a separate, fixed-speed compressor.
“Placing higher demand on the L75RS in this way has the effect of raising the temperature of the heat recovery unit, which in turn is reducing the demands on the gas-fed boiler.
“As a result, the boiler is working up to 66% less and at times, is not required at all, creating significant cost and carbon reduction savings.”
